How does a mobile phone unlock a shared bicycle?

With the development of the Internet and the popularity of smart phones, shared bicycles, as a new way of travel, have brought great convenience to people and solved the problem of the last kilometer of travel. You only need to use your mobile phone to scan the QR code on the bicycle to unlock and use the shared bicycle, which is very convenient. So how does a mobile phone unlock a shared bicycle?

There are three most common ways to unlock shared bicycles, namely mobile communication unlocking, Bluetooth communication unlocking and pure mechanical unlocking. The bicycle lock that uses pure mechanical unlocking does not have an integrated circuit module. It is just a device similar to a luggage password lock. Each bicycle has a specific number and password. When people scan the QR code with their mobile phones, the mobile phone background will retrieve the password of the bicycle and send it to the mobile phone. Enter the password to unlock the bicycle. Since the password of each bicycle is fixed, once the password is remembered, you can skip the step of scanning the code to unlock and directly enter the password to unlock. Therefore, this unlocking method has caused a large number of bicycles to be privately occupied, which in turn caused an increase in the operating costs of shared bicycles.

Early mobile communication unlocking was achieved by sending text messages. The smart lock of the shared bicycle is integrated with a SIM card with an independent number. When the QR code on the shared bicycle is scanned with a mobile phone APP, the mobile phone sends the unique number information of the bicycle to the background, and the background can query the location and status of the bicycle. After confirming the unlocking command, the cloud server will send an unlocking text message to the SIM card of the bicycle. After receiving the text message, you will hear the motor in the lock turn and the lock sheath "snap", and the unlocking is successful. The advantage of SMS unlocking is that the unlocking success rate is relatively high, and the unlocking does not require GPRS/3G traffic, which is more power-saving. But its disadvantage is that the unlocking time is relatively slow, because after sending the unlocking command, you still need to wait for the delivery of the text message.

With the popularity of shared bicycles and the improvement of bicycle power supply technology, the SMS control unlocking method has been gradually eliminated, and the unlocking command is sent using 2G network signals, which greatly shortens the unlocking time. The unlocking waiting time has been reduced from 30 seconds or 1 minute to 3 seconds. However, the problem of unlocking using network signals also comes with it. The unlocking time and unlocking success rate are highly dependent on the signal. The unlocking success rate will be greatly reduced in areas with weak signals.

In order to solve the problems caused by unlocking with network signals, Bluetooth communication unlocking came into being. When the mobile phone APP scans the bicycle QR code, the Bluetooth module inside the bicycle smart lock is paired with the mobile phone Bluetooth. The APP sends the bicycle information to the background. When receiving the unlocking command, the server only needs to send the unlocking command to the mobile phone, and then send the command to the smart lock through the mobile phone Bluetooth to control the motor to unlock. In this way, communication with the SIM card module in the lock is avoided, unlocking is no longer dependent on the signal strength of the smart lock, and power consumption is greatly reduced.

The disadvantage of Bluetooth communication unlocking is that it requires the Bluetooth function of the mobile phone to be turned on all the time. In order to save power, people usually choose to turn off the Bluetooth function, which requires people to manually turn on Bluetooth before unlocking. At present, most shared bicycles on the market use mobile network signals + Bluetooth to assist in unlocking, which greatly reduces the power consumption of unlocking. At the same time, it does not need to rely on the signal strength of the module in the lock, which improves stability. The traffic speed of 4G mobile phones also guarantees the unlocking time.

With the development of technology, shared bicycle companies are actively seeking cooperation with communication companies to develop new unlocking methods. I believe that in the near future, the innovative unlocking technology of shared bicycles will bring us a more convenient, stable and safer user experience.

This article was scientifically reviewed by Zhang Zhongbao, associate professor of computer science and technology research at Beijing University of Posts and Telecommunications.